钼及La_2O_3对激光原位合成TiC-VC颗粒增强镍基复合涂层组织和性能的影响

研究添加钼粉及稀土氧化物La_2O_3对Km TBCr15Mo高铬铸铁表面激光原位合成TiC-VC颗粒增强镍基复合涂层组织及耐磨性的影响,分析钼及La_2O_3的作用机理。结果表明,熔覆层无裂纹且组织致密,熔覆层的组织主要由(Fe,Ni)固溶体,细小颗粒状或树枝状TiC-VC复合碳化物组成。随着钼粉的加入,熔覆层的组织更为均匀,钼元素起到细化晶粒的作用,使弥散分布的TiC、VC颗粒难以聚集长大。随着La_2O_3的加入,熔覆层的形核核心增多,更多的雪花状TiC-VC弥散分布于熔覆层组织中。由于钼具有较强的碳化物形成能力以及对显微组织起到晶粒细化作用,La_2O_3对显微组织的细化及涂层的净化具有较大作用,因此适当的钼粉(5%)或稀土La2O3能提高熔覆层的硬度及耐磨性。

Effect of Mo and La2O3 on Microstructure and Properties of Laser Caldding Ni-Based Composite Coatings Reinforced by in-situ Multiple TiC-VC Carbide Particles

The effects of Mo and La2O3 addition on microstructure and wear properties of laser clad composite coatings on KmTBCr15Mo with Ni-based composite coatings reinforced by in-site multiple TiC-VC carbide particles have been investigated.The clad layer is perfect and mainly composed of (Fe,Ni) solid solution,fine particle or dendritic TiC-VC composite carbides.The additions of Mo can refine the micro-structure and Make the dispersion of TiC, VC particles difficult to grow up. The additions of rare earth oxide La2O3 can increase cladding layer nuclei and more snow shaped TiC-VC particles distributed in the tissues of the cladding layer.Since not only can Mo promote the formation of carbides can also form more shaped TiC-VC particles distributed in the tissues of the cladding layer and La2O3 can refine micro-structure and purify the coating,Appropriate Mo(5%) or rare earth oxide La2O3 can enhanced hardness and wear resistance of the cladding layer.